If you’re unaware, prototype.js is the javascript library that ships with Ruby on Rails. It provides a lot of convenience features for the DHTML / front-end developer.

I’ve been using this resource for my prototype.js doc needs to date.

Found out today that there’s now an official prototype.js doc reference. Hell yeah.

Update

Forgot to mention this dope set of enhancements to prototype as well. Adds a ton of cool stuff like the ability to trigger event handlers programmatically.